Magnesium- and strontium-co-substituted hydroxyapatite: the effects of doped-ions on the structure and chemico-physical properties

Valentina Aina, Gigliola Lusvardi (Corresponding Author), Basil Annaz, Iain R Gibson, Flora Elisabeth Imrie, Gianluca Malavasi, Ledi Menabue, Giuseppina Cerrato, Gianmario Martra

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The present study is aimed at investigating the contribution of two biologically important cations, Mg2+ and Sr2+, when substituted into the structure of
hydroxyapatite (Ca10(PO4)6(OH)2,HA). The substituted samples were synthesized by an aqueous precipitation method that involved the addition of Mg2+- and Sr2+-containing precursors to partially replace Ca2+ ions in the apatite structure. Eight substituted HA samples with different concentrations of single (only Mg2+) or combined (Mg2+ and Sr2+) substitution of cations have been investigated and the results compared with those of pure HA. The obtained materials were characterized by X-ray powder diffraction, specific surface area and porosity measurements (N2 adsorption at 77 K), FT-IR and Raman spectroscopies and scanning electron microscopy. The results indicate that the co-substitution gives rise to the formation of HA and ß-TCP structure types, with a variation of their cell parameters and of the crystallinity degree
of HA with varying levels of substitution. An evaluation of the amount of substituents allows us to design and prepare BCP composite materials with a desired HA/ß-TCP ratio.

Original languageEnglish
Pages (from-to)2867-2879
Number of pages13
JournalJournal of Materials Science: Materials in Medicine
Issue number12
Early online date29 Sep 2012
Publication statusPublished - Dec 2012



  • hydroxyapatite
  • biomaterials
  • calcium phosphates
  • substituted hydroxyapatites

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